1. Technical Field
The present disclosure relates to electrosurgical systems. More particularly, the present disclosure relates to systems, apparatus and methods for isolated data transfer using an electric-field capacitive coupler.
2. Discussion of Related Art
Electrosurgical instruments have become widely used by surgeons. Electrosurgery involves the application of thermal and/or electrical energy to cut, dissect, ablate, coagulate, cauterize, seal or otherwise treat biological tissue during a surgical procedure. Electrosurgery is typically performed using a handpiece including a surgical instrument (e.g., end effector, ablation probe, or electrode) adapted to transmit energy to a tissue site during electrosurgical procedures, an electrosurgical generator operable to output energy, and a cable assembly operatively connecting the surgical instrument to the generator. The basic purpose of both monopolar and bipolar electrosurgery is to produce heat to achieve the desired tissue/clinical effect.
In monopolar electrosurgery, devices use an instrument with a single, active electrode to deliver energy from an electrosurgical generator to tissue, and a patient return electrode or pad that is attached the patient (e.g., a plate positioned on the patient's thigh or back) as the means to complete the electrical circuit between the electrosurgical generator and the patient. When the electrosurgical energy is applied, the energy travels from the exposed or active electrode, to the surgical site, through the patient and to the return electrode. In bipolar electrosurgery, both the active electrode and return electrode functions are performed at the site of surgery. Bipolar electrosurgical devices include two electrodes that are located in proximity to one another for the application of current between their surfaces. Bipolar electrosurgical current travels from one electrode, through the intervening tissue to the other electrode to complete the electrical circuit. Bipolar instruments generally include end-effectors, such as grippers, cutters, forceps, dissectors and the like. Electrosurgical generators are employed by surgeons in conjunction with a variety of types of monopolar and bipolar electrosurgical instruments to perform various types of electrosurgery.
Systems for performing an electrosurgical procedure may include a monopolar or bipolar electrosurgical instrument in operative communication with a processor for controlling the delivery of electrosurgical energy from the electrosurgical generator to the surgical instrument during the electrosurgical procedure. The processor may regulate the generator to adjust various parameters of the electrosurgical energy delivered to the patient during the electrosurgical procedure. Parameters of the delivered electrosurgical energy that may be regulated include voltage, current, resistance, intensity, power, frequency, amplitude, and/or waveform parameters.
An electrosurgical generator for supplying electrosurgical energy to tissue may be capable of switching among a plurality of electrosurgical operational modes such as monopolar and bipolar cutting and coagulation. Application duration and characteristics of the electrosurgical energy delivered to the patient may depend on a variety of factors such as the type of surgical procedure to be performed, surgical instrument design, tissue characteristics of the patient, and the progress of the heat distribution within the tissue area that is to be destroyed and/or the surrounding tissue.
In a variety of medical applications a patient isolation barrier is required for patient protection from unwanted and potentially hazardous voltages or currents. Isolation, broadly defined, is the separation of one circuit, component, or system from undesired influences of other circuits, components, or systems. Medical imaging devices may transmit data from isolated patient circuits to image processing circuits. Conventional handpieces typically include a plurality of switches (e.g., to allow the surgeon to change the mode of operation and/or parameters of the delivered electrosurgical energy) and may transmit control signals corresponding to switch positions across an isolation barrier. Control signals may cross this barrier by a variety of means, including magnetic coupling, optical coupling, and capacitive coupling.
Electromagnetic isolation uses a transformer to couple a signal across an isolation barrier, e.g., air or some other form of non-conductive barrier, by generating an electromagnetic field proportional to the electrical signal. The electromagnetic field may be created and detected by a pair of conductive coils. Optical coupling is the transmission of light across a transparent nonconductive barrier, typically an air gap, to achieve isolation. The light intensity is proportional to the measured signal. The light signal is transmitted across the isolation barrier and detected by a photoconductive element on the opposite side of the isolation barrier. Capacitive isolation is based on an electric field that changes with the level of charge on a capacitor plate. This charge is detected across an isolation barrier and is proportional to the level of the measured signal.
A need exists for reliable isolating devices suitable for use to transmit control signals from a handpiece to an electrosurgical power generator.